[JackOfAllTrades]

Yes it's scope. You're creating the lopm variable inside the function_lopmeter function. How is kakellength, kakelwidth, and fogwidth visible to the rest of the class?

[JackOfAllTrades]

Where are the variables in that latest code? I don't see any except in the button Click handler?

As to why the value is 0, the answer is integer division. When dividing integers, you're always going to get an integer result (and hell, you're ASSIGNING it to an integer). If you have an integer 1 and you divide it by the integer 3 and assign it to an integer variable, what would you expect the integer variable to contain?

[Kilorn]

You've still got the same problem that you had to begin with. You're declaring the variables inside functions, which means that these variables are not visible to any other portion of your code. Scope is an important thing to learn for any programmer. Declare your variables inside the class, but outside of any functions, then you can use the functions to alter the values of those variables, and call the functions that do your calculations inside your button press function.

[Sergio Tapia]

That's because your FB19() method is the only one that TOUCHES the kg_fog variable, yet the FB19() method is never called anywhere.

[Sergio Tapia]

Your variable names are giving me a headache.

Just follow your logic and you'll see what's going on. I'm sure something you THINK is firing, isn't actually firing. Use breakpoints and go step by step.

[Mitja Bonca]

Try this code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace fogmassa
{
    public partial class fogmassa : Form
    {
        float kakelwidth;
        float kakellength;
        float kakelthick;
        float fogwidth;
        float lopm;
        float basvikt;
        float kg_fog;
 
        public fogmassa()
        {
            InitializeComponent();
       
        }

       
        private void txtWidth_TextChanged(object sender, EventArgs e)
        {
            if (txtWidth.Text != "")
            {
                kakelwidth = float.Parse(txtWidth.Text);
            }
        }

        private void txtLength_TextChanged(object sender, EventArgs e)
        {
            if (txtLength.Text != "")
            {
                kakellength = float.Parse(txtLength.Text);
            }
        }

        private void txtThick_TextChanged(object sender, EventArgs e)
        {
            if (txtThick.Text != "")
            {
                kakelthick = float.Parse(txtThick.Text);
            }
        }

        private void txtFogWidth_TextChanged(object sender, EventArgs e)
        {
            if (txtFogWidth.Text != "")
            {
                fogwidth = float.Parse(txtFogWidth.Text);
            }
        }

        private void lopmeter()
        {
            lopm = ((1 / (kakelwidth + fogwidth)) + (1 / (kakellength + fogwidth) * 1000));
        }

        private void kilo()
        {
            lopmeter();
            basvikt = ((fogwidth/100)*(kakelthick/100)*(lopm*100));
        }
    
        private void FB19()
        {
            kg_fog = basvikt * 2.1f;
        }
        private void btnCalc_Click(object sender, EventArgs e)
        {
            kilo();
            FB19();            
            lblLopM.Text = ("Mängd fog: " + kg_fog + " kg");
        }
    
    }
}

This should work now.
Where was the catch you will ask?
In your last method, you called 1st the method FB19() and then kilo(). Wrong. Method FB19() has the variable "basvikt", which is only set in method kilo(). So kio() has to be called first.

You only HAVE TO make sure that variables:
- fogwidth
- kakelthick
- lopm
are set before buttonCalc is clicked!

Hope this has salved the issue here.
bye
Mitja

This post has been edited by Mitja Bonca: 23 November 2010 - 11:33 AM